Placing – and monitoring — cameras to capture footage of coral bleaching was a logistical challenge.

Courtesy of Netflix

A new documentary came out on Netflix last week. It’s called "Chasing Coral," and it looks at the impact of coral bleaching on reefs.

Dr. Mark Eakin runs the Coral Reef Watch program for the National Oceanic and Atmospheric Administration, and he served as a chief scientific advisor for the film. He spoke with WLRN's Nancy Klingener about the movie and about the primary threat facing corals.

WLRN: What is Coral Reef Watch?

EAKIN: Coral Reef Watch is a program that uses primarily satellites but also climate models to look at the ocean temperatures that cause coral bleaching around the world.

What is coral bleaching and what causes it?

Before we say what coral bleaching is, I think we need to explain what a coral is because most people don’t know. And if you think about the children’s game 20 Questions, what’s the first question? Animal, vegetable or mineral? And the unique thing about corals is they’re all three.

Credit Courtesy of Netflix

So you have an animal. And living inside the tissues of this animal are microscopic algae, the plant or vegetable portion. These algae in their tissues are photosynthesizing, making energy from the sun just like leaves on trees or grass. And so these provide the primary food for the corals. The coral itself is clear so the light can get through to these algae. When the high temperatures cause a breakdown in the relationship between the coral animal and these algae, the corals are forced to spit them out into the water, because the algae actually start producing toxins that would kill the coral. So they spit these out. It leaves the tissue clear and you can see right through the clear tissue to the white skeleton underneath.

Now we’re getting to the last of the three, the mineral portion, because corals are building a limestone skeleton. Coral have actually ejected their food source. They’re now starving; they’re injured but trying to survive. If the stress lasts long enough, then the coral will die and the whole thing will get covered over with mossy algae and look really ugly and start to break down very quickly.

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In an extended interview with WLRN, Dr. Mark Eakin of NOAA's Coral Reef Watch discusses the condition of Florida's reef tract and what South Floridians can do to help protect corals.

What was your role in the documentary "Chasing Coral?"

They needed to get out to the places where the bleaching was going to happen to put the cameras in place and film the bleaching. So we provided them with, from our climate model work, the best estimates of where it was likely to be bleaching in the coming months.

Credit Courtesy of Netflix

What do you think this film brings to the conversation?

It shows people how spectacular these places are, how beautiful they are and how important these ecosystems are. The second thing is it shows that this is a system that has been affected by climate change now for over 30 years.

This is not some far distant future. Climate change is affecting coral reefs now and we need to be working to shift to a clean energy economy and reduce the CO2 in the atmosphere if coral reefs are going to have a chance.

We hear so much bad news about coral reefs. Is there any reason for hope?

The last three years has actually been tough. It has been very challenging, emotionally. I’ll get in reports of severe bleaching and pictures and sometimes just have to walk away from my computer and come back later because it’s getting so depressing.

But at the same time, there’s some great stories of hope, and Florida has been right at the cutting edge. The efforts that have gone on for nurseries to grow corals, put them back out on the reef, some of that work was very much innovated and developed right there in the Florida Keys. That’s a great step in the right direction.

But — just imagine: If you’ve got a really polluted river and all of the fish have died and so you stock it with a whole bunch of new fish, if it’s still polluted they’re going to die. So until we deal with the climate change issue, all of these others are patches that are not going to be able to hold.